Dispersion adhesives for flat lamination
The term ‘flat lamination‘ comprises a wide range of applications, products, and substrates in the wood and furniture industry. However, they all have one thing in common: Flat lamination is the partial or full-surface bonding of two or more substrates or substrate layers.
In the modern furniture or wood-based material manufacture, carrier boards are coated with the most different surfaces. Frequently used materials apart from decor papers and veneers are thermoplastic foils, CPL, and HPL. The fields of application are vast: In the door and flooring industry multi-layer assemblies are manufactured in a single operation. From the core layer to possible functional layers and to the finished surface, operations and Pressing times can thus be reduced. Multi-layer modular assemblies have become established in the flooring industry. Materials like PET, TPU, or vinyl require special adhesive systems to reach maximum adhesion. Jowacoll® foil adhesives are adapted precisely to those requirements. The adhesion and moisture resistance can be increased further in individual applications by mixing a crosslinker into the adhesive. Adhesives based on urea formaldehyde (UF) resins were the state of the art for many years. Lately, they have increasingly come under critical scrutiny due to modern health and environmental concerns and are unsuitable for many of the new materials. The dispersion adhesives of the Jowacoll® series are among the efficient alternatives due to lower VOC emissions and therefore a reduction of harmful ingredients.
The portfolio of Jowacoll® dispersion adhesives provides the right adhesive for all applications, all substrates to be bonded and the individual process conditions. Whether to prevent the bleeding through veneers or to minimise the moisture when bonding non-absorbent substrates – special formulations of the dispersions ensure maximum quality.
For laminating wood-based substrates with thermoplastic foils (e.g. PVC, PMMA, ABS, PET), laminates (e.g. CPL, HPL), resinated decor paper (e.g. finish foils), or veneer.
Directions for use
Jowacoll® dispersion adhesives for flat lamination can be applied by roller, spraying, curtain coating, or as a bead. Depending on the application method, adhesives with the suitable specification, e.g. viscosity, should be chosen.
In general, the properties and the type of the substrates to be bonded should be taken into consideration when choosing an adhesive. Porous and moisture-absorbing substrates like veneer require another adhesive compared to non-absorbent substrates with a low surface tension. An example for this are bonding operations involving materials based on polymer.
Dispersion adhesives are largely physically drying systems and therefore the ambient conditions at the place of processing play a major role. Also, one of the substrates needs to be absorbent. High temperatures and low humidity reduce the assembly and Pressing times. The minimum film-forming temperature (in short MFFT) is the lowest temperature of the substrates, ambient air, and adhesive at which the polymers will coalesce to a continuous film and form a resistant adhesive film. MFFT can vary from adhesive to adhesive. Reactive dispersions continue to crosslink for several days after they have been applied and usually reach their final strength after 7 days.
Please observe our technical data sheets and let our Application Specialists advise you before processing adhesives.
PVAc dispersion adhesives are usually classified into four durability classes (D1 – D4) based on their moisture resistance according to the EN 204 standard. Jowat supplies a range of different adhesives for each durability class. The product portfolio provides a broad spectrum of products for indoor applications (relative humidity <15 %), for wet environments (high humidity and short-term exposure to water), as well as for outdoor applications exposed to weathering with an appropriate surface protection.
A testing procedure for heat resistance is described in DIN EN 14257 (WATT ‘91). The standard only specifies how heat resistance is to be evaluated and does not prescribe a minimum requirement. There is only a minimum requirement for manufacturing window scantlings. RAL-certified window scantlings have to meet a minimum tensile shear strength of 7 N/mm². Many Jowacoll® dispersions fulfil this requirement.